This invention relates broadly to a packaging machine installed, for example, at a packing center for producing a packaged product by wrapping up an article or articles placed on a tray by using a film piece. More particularly, this invention relates to a device for supplying such a film piece as a part of such a packaging machine.
Packaging machines of the kind using a stretch film to package products placed on a tray are commonly used at packing centers for products to be sold at supermarkets. A packaging machine of this kind (described, for example, in Japanese Patent Publication Tokkai 63-218025) is typically so structured that a film in the form of a web is pulled from a film roll to a packaging station above the product to be packaged and is used to wrap up the product after it is cut to a specified length. A prior art film supplying device for such a packaging machine may be characterized, as shown in FIG. 13, as having a film roll FL and a film feeder 6 such that a film F which is pulled out from the film roll FL is guided to the film feeder 6 and is thereby kept stretched. Clamps (not shown) for the film F are provided on both sides of the film feeder 6, and these clamps are adapted to move to the right (with reference to the figure) from the film feeder 6 to grip the film F and thereafter to return towards the film feeder 6, thereby supplying the film F to the film feeder 6. The film F is thereafter cut by means of a cutter 21.
According to the prior art technology described above, however, each cycle of the film supply operation takes a relatively long time because the clamps provided to the film feeder 6 must first move towards the film F and then back towards the film feeder 6. As a result, the period of the cyclic packaging operations cannot be shortened.